The present invention relates to a recording medium and a recording and reproducing system for the recording medium.
Heretofore, there is known the DVD (digital versatile disc),the DVD-R (DVD WRITE ONCE) and the DVD-RW (DVD-Re-Writable) as the rewritable disc.
As shown in the Japanese Patent Laid-Open Publication No. 9-17029, the DVD-R or DVD-RW (hereinafter called DVD) has a spiral or co-axial groove for recording information, a land between the grooves and a plurality of land prepits formed between the grooves. The land prepit is provided with various sets of information such as the address.
In such a disc, it is possible to read the information recorded on the groove and the information recorded on the land prepit at the same time.
However, there is a problem that signals reproduced from the information recorded on land prepits affect the RF signal reproduced from the information recorded on the groove as offset.
An object of the present invention is to provide a recording medium wherein information recorded on the groove and the land prepit can be accurately read out and a system capable of recording and reproducing with accuracy.
According to the present invention, there is provided a recording medium having a circular substrate, grooves formed on the substrate, a land formed between the grooves, a plurality of land prepits formed between the grooves, wherein the groove and the land prepit are formed so as to satisfy a following formula,
Gw/(xcex/NA)=0.2093{Lp/(xcex/NA)}2xe2x88x920.4342Lp/(xcex/NA)+0.332
where Gw is the width of the groove, Lp is the length of the land prepit in a radial direction of the substrate, Gd is the depth of the groove, xcex is the wave length of light used in a system for recording information on the recording medium, and NA is the numerical aperture of an objective in the system.
The present invention further provides a recording medium having a circular substrate, grooves formed on the substrate, a land formed between the grooves, a plurality of land prepits formed between the grooves, wherein the groove and the land prepit are formed so as to satisfy following formulae;
Gw/(xcex/NA)xe2x89xa70.2093{Lp/(xcex/NA)}2xe2x88x920.4342Lp/(xcex/NA)+0.332xe2x88x92(xe2x88x922.64Gd+0.1276)
Gw/(xcex/NA)xe2x89xa60.2093{Lp/(xcex/NA)}2xe2x88x920.4342Lp/(xcex/NA)+0.332+(xe2x88x924.48Gd+0.2112)
where Gw is the width of the groove, Lp is the length of the land prepit in a radial direction of the substrate, Gd is the depth of the groove, xcex is the wave length of light used in a system for recording information on the recording medium, and NA is the numerical aperture of an objective in the system.
The present invention still further provides a system of recording a medium having a circular substrate, grooves formed on the substrate, a land formed between the grooves, a plurality of land prepits formed between the grooves, wherein a wavelength of light for recording information on the medium and a numerical aperture of an objective of the system are provided so as to satisfy following formulae,
Gw/(xcex/NA)xe2x89xa70.2093{Lp/(xcex/NA)}2xe2x88x920.4342Lp/(xcex/NA)+0.332xe2x88x92(xe2x88x922.64Gd+0.1276)
Gw/(xcex/NA)xe2x89xa60.2093{Lp/(xcex/NA)}2xe2x88x920.4342Lp/(xcex/NA)+0.332+(xe2x88x924.48Gd+0.2112)
where Gw is the width of the groove, Lp is the length of the land prepit in a radial direction of the substrate, Gd is the depth of the groove.